What causes a 94 Toyota t-100 to idle rough and wants to die but fine when driving at normal speeds?

A rough idle in a 1994 Toyota T-100 that resolves during normal driving can be caused by several factors. Common issues include a dirty or failing idle air control valve (IAC), vacuum leaks, or malfunctioning spark plugs and ignition components. Additionally, fuel delivery problems, such as a clogged fuel filter or failing fuel pump, could contribute to poor idling. It's advisable to perform a thorough inspection of these components to diagnose and resolve the issue.